1. Field of the Invention
The present invention relates to a lighting configuration emitting light of a predefined spectrum with a high S/P ratio at common practical CCT values, in particular to a lighting configuration emitting light of a spectrally enhanced spectrum for improved visual acuity under mesopic and photopic conditions.
2. Description of the Related Art
Certain prior art lighting configurations aim at improving visibility under mesopic conditions.
PCT Application WO2006/132533 A2 relates to a lighting configuration that provides an improved visibility compared with conventional utility lighting. The lighting configuration is designed to emit light in a first wavelength region and light in a second wavelength region. The first wavelength region comprises wavelengths of 500-550 nm. The second wavelength region comprises wavelengths of 560-610 nm. The lighting unit is designed to generate light having a dominant wavelength from the first wavelength region in such a way that the eye sensitivity of the human eye is dominated by rods.
WO 2009/013317 A1 relates to a lighting configuration for illuminating an area under mesopic conditions. The lighting configuration has one or more LEDs emitting substantially monochromatic light in a first wavelength region. The lighting configuration further has one or more LEDs emitting substantially monochromatic light in a second wavelength region. Thereby, the combination of LEDs is such that, in use, the light provided by the lighting configuration has a ratio of scotopic to photopic light (S/P-ratio) greater than 2.
EP 2469983 A2 claimed improvements by illuminating an area under mesopic conditions by applying blue LEDs covered with a colour conversion layer emitting light in the range of a first intensity peak at a wavelength of 440 to 480 nm and a second intensity peak (12) at a wavelength of 600 to 650 nm. Preferred embodiments comprise LEDs with a third color conversion layer emitting light having a wavelength in the 550-590 nm range.
US 2006/0149607 discloses a lighting configuration comprising at least two light sources emitting light of different wavelengths. One light source has a wavelength substantially corresponding to the scotopic maximum (505 nm); a second light source has a wavelength substantially corresponding to the photopic maximum (555 nm).
The prior art reflects an incomplete understanding of the contributions of specific parts of the visible spectrum to the overall performance of a lighting configuration in providing optimum visual acuity.
Thus, there is a need for a lighting configuration providing spectrally enhanced light for improved visual acuity.